# Moderate Number System Solved QuestionAptitude Discussion

 Q. 2ab5 is a four-digit number divisible by 25. If the number formed from the two digits ab is a multiple of 13, then $ab =$
 ✖ A. 10 ✖ B. 25 ✔ C. 52 ✖ D. 65

Solution:
Option(C) is correct

We have given that the number $2ab5$ is divisible by 25.

Any number divisible by 25 ends with the last two digits 00, 25, 50, or 75.
So, $b5$ should equal 25 or 75.

Hence, $b = 2$ or $7$.
Since $a$ is now free to take any digit from 0 through 9, $ab$ can have multiple values.

We also have that $ab$ is divisible by 13.
The multiples of 13 are $13, 26, 39, 52, 65, 78$ and $491$.

Among these, the only number ending with 2 or 7 is 52.

Hence, $ab=52$

## (1) Comment(s)

Shobia
()

from the question we can clearly understand that ab is a multiple of 13,,

so from the above 4 option 52 is only a multiple of 13.

so ans:52